Process of making commutators.



No. 842,829. PATENTED JAN. 29, 1907.-

T.DUNGAN. I PROCESS OF MAKING GOMMUTATORS.

APPLICATION FILED JAN. 23,1906.

g, 3 0 E g v1 ll iiliililihlililililllI- n TED STATES 1 .4mm: OFFICE.

THOMAS DUNCAN, OF LA FAYETTE, INDIANA, ASSIGNOR TO DUNCAN ELECTRIC MANUFACTURING COMPANY, OF LA FAYETTE, INDIANA, ACORPORATION OF ILLINOIS.

PROCESS OF' MAKING COIVIMUTATORS.

iiio. 842,829. Specification of Letters l atent. Patented Jan. 29, 1907.

Original application filed March 14, 1904, Serial No. 197,913. Divided and this application filcduanum'y '23, 1905. Serial No. 242.410.

T (I'll ll/hill", 4 1/ ("HI/(16771! i the precious metal are preferably not coex- Be it known that I, TnOMAs DUNCAN, a

. citizen of the United States, residing at La Fayette,.in the county of Tippecanoe and State of Indiana, have invented a certain new and useful Improvement in Processes of Making Commutators, (being a division of ,myapplication, Serial No. 197,918, filed March 14, 1904,) of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to electric-motor meters, and has for its object an improvement in the method of constructing commutators that may have metal in their fOIlIlfiilOil having great conductivity and to make the commutators inexpensive.

The present application for patent relates to the process disclosed in my copending application, Serial No. 197,913, filed March 14,

1904, of which this application is a division.

The metal of superior conductivity in qualit that referabl enters into the construcy Y tion of t e commutator is silver that preferably is unalloyed. The commutator madeby the process of the invention, generally speaking, may be described as one whose segments are of composite formation,- each segment GOIIIPI'lSlDg a body portion of baser metal, as copper, and a facing of precious metal, as silver, the facings being designed to be engaged by the commutator-brushes of the meter. In making these commutators I su erpose a tube of recious metal about a e of baser metal, razing or soldering the two tubes together, whereafter the. com- ,posite tube is slotted to form the segments,

which are secured in place, preferably by means of a core of insulating material, within the slotted tube and rings of insulating ma terial around the segments andjholding the same upon the core of insulatingmaterial. In theinitial formation of the commutator the slots desirably extend beyond the core of insulating material and the binding-rings of insulating material, the slots desirably not extending to the ends of the tubes, so that the segments of the commutator to be are held in proper relative positions until said core of insulating material and until said binding-rings of insulating material are placed in position, Whereafter the unslotted ends of the tube are cut off. The portions of 'iensive in length with the entire commutator-segmen: s, such lengths of precious metal being desirably res.rici ed to the space between ihe rings of insulating maicrial or to substamially -this space, the portions of the commu. a1or-segmen.s that extend below the lower ring being desirably of the same base me-Lal and preferably fanned out for the purpose of a-..aehing armamre-wires thereto. The composite tubes are desirably formed by first taking a s-.ri;') of the baser metal, as copper, forming or rolling a groove therein, and filling this groove \Vlill the precious metal, as silver, which may be brazed or soldered to the baser part. The composite strip of metal thus formed is cut into sections which when rolled will form a tube of the diameter that the commmator is to be, which tube is put through the process above described.

I will explain my invention more fully by reference to the accompanying drawings, in

c which- Figure 1 illustrates a composite sheet of baser and precious metal. Fig. 2 is a crosssectional view on line 2 2 of Fig. 1. Fi 3 is a cross-sectional view on line 3 3 of *ig. 1. Fig. 4 is a view of a section of the composite sheet metal of a size suflicient to form the commutator. Fig. 5 indicates the sheet shown in Fig. 4 rolled into a tube. Fig. 6 is a longitudinal section of the composite tube shown in Fig. 5. Fig. -7 shows the tube of Fig. 5 slotted. Fig. 8 is a longitudinal sectional view of. the slotted tube shown in Fig. 7 with a plug or core of insulating material added. Fig. 9 shows the tubes of Figs. 7 and 8 with bindinginsulation-rings added. Fig. 10 is a view similar to Fig. 9, showing the rings, however, rounded oif and the unslotted ends of the composite tube removed.

Fi 11 is a plan view of the structure shown 1 in ig. 10. Fig. 12 is a view similar to Fig. 10, showing the segments fanned out for purpose of connection with armature-terminals.

strip of baser metal a, desirably of copper,

and preferably form therein a groove 1; of a width slightly in excess of the contact or brush-en aging zoneof the commutator and place wit in said groove the strip ofmetal c of superior conductivity, as silver, gold, no

platinum, or other such metal, it being preferably secured in position by brazing or soldering.

The strip a is preferably rolled separably from the strip 0, and the composite stripe and c is again rolled after said strip 0 has been inserted to make the surfaces smooth and parallel.

cerned is ahomogeneous structure.

lengths, as indicated in Fig. .l, a single section being indicated in Fig. 4.

inder, as iniiicated. in Figs. 5.an l 6, the cylinders all having the same diameter. The

meeting edges of the strip (indicated at the line d) are preferably soldered or brazed, after which the tubes are slotted nearly their en- Each section I (indicated in Fig. 4 is then turned into a cyl After this is done the 5 composite strip is quite smooth and so far as i mechanical and electrical conditions are con-H The composite strip is afterward. cut up into i l l i tire lengths, as indicated at 0, Figs 7, 8, an! 9. The first saw-cut is desirably along the meeting edges (Z to obliterate traces ofsoldel. The continuous endsj of the tube are preferably in place until after the core or cylinder g, of insulating material, has been inserted and until the binding-rings it have been I forced over the tube to secure firm cngagement between the tube-segments and the iiisulating core or sleeve 9. The insulating Z binding-rings it may be rounded, if preferreai, as indicated in Figs. 1.0, 11, and 12. After the firm mechanical engagement between the slotted portions of the tube, the insulatlu -sleeve g, and the insulating-rings It has been eflected the upper end of the tube is preferably cut away along the upper plane silver or gold, while the balance of the commutator-strip may be made from copper, brass, or other similar metal. When silver is employed in the construction of commutators, my invention enables the reductionin I cost over the old method of about sixty per name this 9th day of January,

cent., the product being in every way as strong and serviceable as if made from the solid tube.

While I have herein shown and particularly described the preferred way of making the commutator of my invention, I do not wish to be limited to the precise details shown; but,

Having thus described .my invention, I claim as new anddesire to secure by Lett ers Patent 1. The process of making commutators for meter-motors, which consists in fastening a strip of precious metal upon a strip of inferiormetal toform a composite strip, dividing said composite strip into lengths which, when rolled, will form tubes of the diameter to be made, rolling said lengths into such tubes, slotting and separating said tube into commutator-segments, and holding the con'nuutatorsegments in fixed mechanical relation, substantially as described.

2. The process of making commutators for meter-motors, which consists in farming a groove in a strip of inferior metal, placing a strip of precious metal in said groove and fastening said strip of precious metal to its companion strip to form a composite strip and dividing said composite strip into lengths which, when rolled, will form tubes of the diameter of the (.ommutatcrs that are to be made, rolling said lengths into a tube, slotting and separating said tube into cominutater-segments, and holding the commutator-segments in fixed mechanical relation,

I substantially as described.

3. The process of making comn'iutators for meter-motors, which consists in forming a groove in a strip of inferior metal, placing a strip of silver in said groove and fastening said strip of silver to 1ts companion strip to form a composite strip and dividing said composite strip into lengths which, when rolled, will form tubes of the diameter of the commutators that are to be made, rolling said lengths into a tube, slotting and separating said tube into commutator-segments, and holding the commutator-segments i-n fixed mechanical relation, substantially as described.

4. The process of making commutators for meter-motors, which consists in establishing a groove in a bod of metal, inserting a body of precious meta in said groove, and subdividing the composite body of metals into commutator-segments.

In witness whereof I hereunto subscribe my A. D. 1905 THOMAS DUNCAN.

Witnesses:

LINN C. Ross, SADIE E. ELY. 

